How to make Vim detect filetype from the shebang line?

Question

Sometimes I write scripts without any filename extension. For example:

#!/usr/bin/env node

console.log('hello world!');

I hope that Vim can detect the filetype from the shebang line (e.g. #!/usr/bin/env node is javascript). What should I put into filetype.vim?

Answer 1

Following the instructions listed in :help new-filetype-scripts, create the scripts.vim file in the user runtime directory (~/.vim/ on Unix-like systems), and write the following script in it:

if did_filetype()
    finish
endif
if getline(1) =~# '^#!.*/bin/env\s\+node\>'
    setfiletype javascript
endif